OPEN Foundation

Ketamine

Habenula Connectivity and Intravenous Ketamine in Treatment-Resistant Depression

Abstract

Background: Ketamine’s potent and rapid antidepressant properties have shown great promise to treat severe forms of major depressive disorder (MDD). A recently hypothesized antidepressant mechanism of action of ketamine is the inhibition of N-methyl-D-aspartate receptor-dependent bursting activity of the habenula (Hb), a small brain structure that modulates reward and affective states.

Methods: Resting-state functional magnetic resonance imaging was conducted in 35 patients with MDD at baseline and 24 hours following treatment with i.v. ketamine. A seed-to-voxel functional connectivity (FC) analysis was performed with the Hb as a seed-of-interest. Pre-post changes in FC and the associations between changes in FC of the Hb and depressive symptom severity were examined.

Results: A reduction in Montgomery-Åsberg Depression Rating Scale scores from baseline to 24 hours after ketamine infusion was associated with increased FC between the right Hb and a cluster in the right frontal pole (t = 4.65, P = .03, false discovery rate [FDR]-corrected). A reduction in Quick Inventory of Depressive Symptomatology-Self Report score following ketamine was associated with increased FC between the right Hb and clusters in the right occipital pole (t = 5.18, P < .0001, FDR-corrected), right temporal pole (t = 4.97, P < .0001, FDR-corrected), right parahippocampal gyrus (t = 5.80, P = .001, FDR-corrected), and left lateral occipital cortex (t = 4.73, P = .03, FDR-corrected). Given the small size of the Hb, it is possible that peri-habenular regions contributed to the results.

Conclusions: These preliminary results suggest that the Hb might be involved in ketamine’s antidepressant action in patients with MDD, although these findings are limited by the lack of a control group.

Rivas-Grajales, A. M., Salas, R., Robinson, M. E., Qi, K., Murrough, J. W., & Mathew, S. J. (2021). Habenula Connectivity and Intravenous Ketamine in Treatment-Resistant Depression. The international journal of neuropsychopharmacology, 24(5), 383–391. https://doi.org/10.1093/ijnp/pyaa089

Link to full text

Plasma BDNF concentrations and the antidepressant effects of six ketamine infusions in unipolar and bipolar depression

Abstract

Objectives: Accumulating evidence has implicated that brain derived neurotrophic factor (BDNF) is thought to be involved in the pathophysiology of depression, but its correlation with ketamine’s antidepressant efficacy focusing on Chinese individuals with depression is not known. This study was aim to determine the correlation of plasma BDNF (pBDNF) concentrations and ketamine’s antidepressant efficacy.

Methods: Ninety-four individuals with depression received six intravenous infusions ketamine (0.5 mg/kg). Remission and response were defined as Montgomery-Asberg Depression Rating Scale (MADRS) scores less than 10 and a reduction of 50% or more in MADRS scores, respectively. Plasma was collected at baseline and at 24 h and 2 weeks after completing six ketamine infusions (baseline, 13 d and 26 d).

Results: A significant improvement in MADRS scores and pBDNF concentrations was found after completing six ketamine infusions compared to baseline (all ps < 0.05). Higher baseline pBDNF concentrations were found in ketamine responders/remitters (11.0 ± 6.2/10.1 ± 5.8 ng/ml) than nonresponders/nonremitters (8.0 ± 5.5/9.2 ± 6.4 ng/ml) (all ps < 0.05). Baseline pBDNF concentrations were correlated with MADRS scores at 13 d (t = – 2.011, p = 0.047) or 26 d (t = – 2.398, p = 0.019) in depressed patients (all ps < 0.05). Subgroup analyses found similar results in individuals suffering from treatment refractory depression.

Conclusion: This preliminary study suggests that baseline pBDNF concentrations appeared to be correlated with ketamine’s antidepressant efficacy in Chinese patients with depression.

Zheng, W., Zhou, Y. L., Wang, C. Y., Lan, X. F., Zhang, B., Zhou, S. M., Yan, S., & Ning, Y. P. (2021). Plasma BDNF concentrations and the antidepressant effects of six ketamine infusions in unipolar and bipolar depression. PeerJ, 9, e10989. https://doi.org/10.7717/peerj.10989

Link to full text

Low Doses of Psilocybin and Ketamine Enhance Motivation and Attention in Poor Performing Rats: Evidence for an Antidepressant Property

Abstract

Long term benefits following short-term administration of high psychedelic doses of serotonergic and dissociative hallucinogens, typified by psilocybin and ketamine respectively, support their potential as treatments for psychiatric conditions such as major depressive disorder. The high psychedelic doses induce perceptual experiences which are associated with therapeutic benefit. There have also been anecdotal reports of these drugs being used at what are colloquially referred to as “micro” doses to improve mood and cognitive function, although currently there are recognized limitations to their clinical and preclinical investigation. In the present studies we have defined a low dose and plasma exposure range in rats for both ketamine (0.3-3 mg/kg [10-73 ng/ml]) and psilocybin/psilocin (0.05-0.1 mg/kg [7-12 ng/ml]), based on studies which identified these as sub-threshold for the induction of behavioral stereotypies. Tests of efficacy were focused on depression-related endophenotypes of anhedonia, amotivation and cognitive dysfunction using low performing male Long Evans rats trained in two food motivated tasks: a progressive ratio (PR) and serial 5-choice (5-CSRT) task. Both acute doses of ketamine (1-3 mg/kg IP) and psilocybin (0.05-0.1 mg/kg SC) pretreatment increased break point for food (PR task), and improved attentional accuracy and a measure of impulsive action (5-CSRT task). In each case, effect size was modest and largely restricted to test subjects characterized as “low performing”. Furthermore, both drugs showed a similar pattern of effect across both tests. The present studies provide a framework for the future study of ketamine and psilocybin at low doses and plasma exposures, and help to establish the use of these lower concentrations of serotonergic and dissociative hallucinogens both as a valid scientific construct, and as having a therapeutic utility.

Higgins, G. A., Carroll, N. K., Brown, M., MacMillan, C., Silenieks, L. B., Thevarkunnel, S., Izhakova, J., Magomedova, L., DeLannoy, I., & Sellers, E. M. (2021). Low Doses of Psilocybin and Ketamine Enhance Motivation and Attention in Poor Performing Rats: Evidence for an Antidepressant Property. Frontiers in pharmacology, 12, 640241. https://doi.org/10.3389/fphar.2021.640241

Link to full text

Functional connectivity between the amygdala and subgenual cingulate gyrus predicts the antidepressant effects of ketamine in patients with treatment-resistant depression

Aim: Approximately one-third of patients with major depressive disorder develop treatment-resistant depression. One-third of patients with treatment-resistant depression demonstrate resistance to ketamine, which is a novel antidepressant effective for this disorder. The objective of this study was to examine the utility of resting-state functional magnetic resonance imaging for the prediction of treatment response to ketamine in treatment-resistant depression.

Methods: An exploratory seed-based resting-state functional magnetic resonance imaging analysis was performed to examine baseline resting-state functional connectivity differences between ketamine responders and nonresponders before treatment with multiple intravenous ketamine infusions.

Results: Fifteen patients with treatment-resistant depression received multiple intravenous subanesthetic (0.5 mg/kg/40 minutes) ketamine infusions, and nine were identified as responders. The exploratory resting-state functional magnetic resonance imaging analysis identified a cluster of significant baseline resting-state functional connectivity differences associating ketamine response between the amygdala and subgenual anterior cingulate gyrus in the right hemisphere. Using anatomical region of interest analysis of the resting-state functional connectivity, ketamine response was predicted with 88.9% sensitivity and 100% specificity. The resting-state functional connectivity of significant group differences between responders and nonresponders retained throughout the treatment were considered a trait-like feature of heterogeneity in treatment-resistant depression.

Conclusion: This study suggests the possible clinical utility of resting-state functional magnetic resonance imaging for predicting the antidepressant effects of ketamine in treatment-resistant depression patients and implicated resting-state functional connectivity alterations to determine the trait-like pathophysiology underlying treatment response heterogeneity in treatment-resistant depression.

Nakamura, T., Tomita, M., Horikawa, N., Ishibashi, M., Uematsu, K., Hiraki, T., Abe, T., & Uchimura, N. (2021). Functional connectivity between the amygdala and subgenual cingulate gyrus predicts the antidepressant effects of ketamine in patients with treatment-resistant depression. Neuropsychopharmacology reports, 41(2), 168–178. https://doi.org/10.1002/npr2.12165

Link to full text

Single, Fixed-Dose Intranasal Ketamine for Alleviation of Acute Suicidal Ideation. An Emergency Department, Trans-Diagnostic Approach: A Randomized, Double-Blind, Placebo-Controlled, Proof-of-Concept Trial

Abstract

Background: Suicidal patients often present to the emergency department, where specific anti-suicidal treatment is lacking. Ketamine, a Glutamate modulator and a rapidly acting antidepressant with anti-suicidal properties, might offer relief.

Aims: Evaluation of single, fixed-dosed intranasal ketamine for acute suicidal ideation in the emergency department.

Methods: Between August 2016 and April 2018, 30 eligible suicidal subjects, scheduled for psychiatric hospitalization, independently of their psychiatric diagnosis, were randomized to intranasal ketamine 40 mg or saline placebo. Safety and efficacy evaluations were scheduled for 30, 60, 120 and 240 min post administration and on days 1, 2, 3, 4, 5, 7, 21 and 28. Primary outcome was suicidal ideation.

Results: Fifteen subjects were randomized for each study group. All were analyzed for primary and secondary outcomes. Four hours post administration, the mean difference in suicidal symptoms between the groups, measured by the Montgomery-Åsberg Depression Rating Scale (MADRS) item of suicidal thoughts (MADRS-SI), was 1.267 (95% confident interval 0.1-2.43, p < 0.05) favoring treatment. Remission from suicidal ideation was evident in 80% for the ketamine group compared with 33% for the controls (p < 0.05). The mean difference in depressive symptoms, measured by MADRS, at the same time was 9.75 (95% confident interval 0.72-18.79, p < 0.05) favoring ketamine. Treatment was safe and well-tolerated. Conclusions: Single, fixed-dose, intranasal ketamine alleviated suicidal ideation and improved depressive symptoms four hours post administration. We present here an innovative paradigm for emergency department management of suicidal individuals. Future larger-scale studies are warranted. ClinicalTrials.gov Identifier: NCT02183272.

Domany, Y., & McCullumsmith, C. B. (2021). Single, Fixed-Dose Intranasal Ketamine for Alleviation of Acute Suicidal Ideation. An Emergency Department, Trans-Diagnostic Approach: A Randomized, Double-Blind, Placebo-Controlled, Proof-of-Concept Trial. Archives of suicide research : official journal of the International Academy for Suicide Research, 1–16. Advance online publication. https://doi.org/10.1080/13811118.2021.1878078

Link to full text

Prolonged ketamine infusion modulates limbic connectivity and induces sustained remission of treatment-resistant depression

Abstract

Ketamine produces a rapid antidepressant response in over 50% of adults with treatment-resistant depression. A long infusion of ketamine may provide durable remission of depressive symptoms, but the safety, efficacy, and neurobiological correlates are unknown. In this open-label, proof-of-principle study, adults with treatment-resistant depression (N = 23) underwent a 96-h infusion of intravenous ketamine (0.15 mg/kg/h titrated toward 0.6 mg/kg/h). Clonidine was co-administered to reduce psychotomimetic effects. We measured clinical response for 8 weeks post-infusion. Resting-state functional magnetic resonance imaging was used to assess functional connectivity in patients pre- and 2 weeks post-infusion and in matched non-depressed controls (N = 27). We hypothesized that responders to therapy would demonstrate response-dependent connectivity changes while all subjects would show treatment-dependent connectivity changes. Most participants completed infusion (21/23; mean final dose 0.54 mg/kg/h, SD 0.13). The infusion was well tolerated with minimal cognitive and psychotomimetic side effects. Depressive symptoms were markedly reduced (MADRS 29 ± 4 at baseline to 9 ± 8 one day post-infusion), which was sustained at 2 weeks (13 ± 8) and 8 weeks (15 ± 8). Imaging demonstrated a response-dependent decrease in hyperconnectivity of the subgenual anterior cingulate cortex to the default mode network, and a treatment-dependent decrease in hyperconnectivity within the limbic system (hippocampus, amygdala, medial thalamus, nucleus accumbens). In exploratory analyses, connectivity was increased between the limbic system and frontal areas, and smaller right hippocampus volume at baseline predicted larger MADRS change. A single prolonged infusion of ketamine provides a tolerated, rapid, and sustained response in treatment-resistant depression and normalizes depression-related hyperconnectivity in the limbic system and frontal lobe. ClinicalTrials.gov : Treatment Resistant Depression (Pilot), NCT01179009.

Siegel, J. S., Palanca, B., Ances, B. M., Kharasch, E. D., Schweiger, J. A., Yingling, M. D., Snyder, A. Z., Nicol, G. E., Lenze, E. J., & Farber, N. B. (2021). Prolonged ketamine infusion modulates limbic connectivity and induces sustained remission of treatment-resistant depression. Psychopharmacology, 238(4), 1157–1169. https://doi.org/10.1007/s00213-021-05762-6

Link to full text

Clinically meaningful changes on depressive symptom measures and patient-reported outcomes in patients with treatment-resistant depression

Abstract

Objective: To use the Clinical Global Impression-Severity (CGI-S) scale to estimate clinically meaningful and clinically substantial changes as measured using the Montgomery-Åsberg Depression Rating Scale (MADRS), the Sheehan Disability Scale (SDS), and the Patient Health Questionnaire-9 (PHQ-9) in patients with treatment-resistant depression (TRD).

Methods: Pooled data were derived from two 4-week, randomized, active-controlled studies evaluating esketamine nasal spray (ESK) plus oral antidepressant (OAD) or OAD plus placebo nasal spray (PBO) in adults with TRD (N = 565). CGI-S, MADRS, SDS, and PHQ-9 scores were obtained at baseline and over 4 weeks of treatment. In this post hoc analysis, change scores on the MADRS, SDS, and PHQ-9 that corresponded to a clinically meaningful (1-point) or clinically substantial (2-point) change on the CGI-S scale were identified.

Results: Clinically meaningful changes in CGI-S scores after 28 days corresponded to 6-, 4-, and 3-point changes from baseline on the MADRS, SDS, and PHQ-9, respectively. Similarly, a 2-point CGI-S score change (clinically substantial change) corresponded to a 12-, 8-, and 6-point change on the MADRS, SDS, and PHQ-9, respectively. The proportion of patients showing substantial clinical improvement in the ESK plus OAD group versus the OAD plus PBO group after 28 days of treatment favored ESK plus OAD: 69.0% vs 55.3% (MADRS), 64.5% vs 48.9% (SDS), and 77.1% vs 64.7% (PHQ-9).

Conclusion: We provide a basis for identifying clinically meaningful and clinically substantial changes as assessed with commonly used outcome measures for depression to facilitate the translation of clinical trial results into clinical practice.

Turkoz, I., Alphs, L., Singh, J., Jamieson, C., Daly, E., Shawi, M., Sheehan, J. J., Trivedi, M. H., & Rush, A. J. (2021). Clinically meaningful changes on depressive symptom measures and patient-reported outcomes in patients with treatment-resistant depression. Acta psychiatrica Scandinavica, 143(3), 253–263. https://doi.org/10.1111/acps.13260

Link to full text

Ketamine and Serotonergic Psychedelics: Common Mechanisms Underlying the Effects of Rapid-Acting Antidepressants

Abstract

Background: The glutamatergic modulator ketamine has created a blueprint for studying novel pharmaceuticals in the field. Recent studies suggest that “classic” serotonergic psychedelics (SPs) may also have antidepressant efficacy. Both ketamine and SPs appear to produce rapid, sustained antidepressant effects after a transient psychoactive period.

Methods: This review summarizes areas of overlap between SP and ketamine research and considers the possibility of a common, downstream mechanism of action. The therapeutic relevance of the psychoactive state, overlapping cellular and molecular effects, and overlapping electrophysiological and neuroimaging observations are all reviewed.

Results: Taken together, the evidence suggests a potentially shared mechanism wherein both ketamine and SPs may engender rapid neuroplastic effects in a glutamatergic activity-dependent manner. It is postulated that, though distinct, both ketamine and SPs appear to produce acute alterations in cortical network activity that may initially produce psychoactive effects and later produce milder, sustained changes in network efficiency associated with therapeutic response. However, despite some commonalities between the psychoactive component of these pharmacologically distinct therapies-such as engagement of the downstream glutamatergic pathway-the connection between psychoactive impact and antidepressant efficacy remains unclear and requires more rigorous research.

Conclusions: Rapid-acting antidepressants currently under investigation may share some downstream pharmacological effects, suggesting that their antidepressant effects may come about via related mechanisms. Given the prototypic nature of ketamine research and recent progress in this area, this platform could be used to investigate entirely new classes of antidepressants with rapid and robust actions.

Kadriu, B., Greenwald, M., Henter, I. D., Gilbert, J. R., Kraus, C., Park, L. T., & Zarate, C. A. (2021). Ketamine and Serotonergic Psychedelics: Common Mechanisms Underlying the Effects of Rapid-Acting Antidepressants. The international journal of neuropsychopharmacology, 24(1), 8–21. https://doi.org/10.1093/ijnp/pyaa087

Link to full text

Ketamine treatment for depression: qualitative study exploring patient views

Abstract

Background: Ketamine is a new and promising treatment for depression but comes with challenges to implement because of its potential for abuse.

Aims: We sought the views of patients to inform policy and practical decisions about the clinical use of ketamine before large-scale roll-out is considered.

Method: This qualitative study used three focus groups and three validation sessions from 14 patients with prior diagnoses of depression but no experience of ketamine treatment. Focus groups explored their views about clinical use of ketamine and the best way for ketamine to be administered and monitored. The qualitative data were analysed by three service-user researchers using thematic analysis.

Results: Five themes were generated: changing public perceptions, risks, monitoring, privacy and data protection, and practical aspects. Participants were conscious of the stigma attached to ketamine as a street drug and wanted better public education, and evidence on the safety of ketamine after long-term use. They felt that monitoring was required to provide evidence for ketamine’s safe use and administration, but there were concerns about the misuse of this information. Practical aspects included discussions about treatment duration, administration and accessibility (for example who would receive it, under what criteria and how).

Conclusions: Patients are enthusiastic about ketamine treatment but need more information before national roll-out. The wider societal impact of ketamine treatment also needs to be considered and patients need to be part of any future roll-out to ensure its success.

Jilka, S., Odoi, C. M., Wilson, E., Meran, S., Simblett, S., & Wykes, T. (2021). Ketamine treatment for depression: qualitative study exploring patient views. BJPsych open, 7(1), e32. https://doi.org/10.1192/bjo.2020.165

Link to full text

Adverse Effects of Esketamine for the Treatment of Major Depression Disorder: Findings from Randomized Controlled Trials

Abstract

Esketamine is a promising drug which can induce antidepressant effects in Major Depression Disorder (MDD). Several randomized controlled trials (RCTs) have been implemented to assess the efficacy and safety of esketamine for the treatment of MDD. Therefore, we carried out a meta-analysis to assess adverse effect profiles of esketamine for the treatment of MDD. We searched RCTs which were implemented from January 2010 to June 2020 by searching PubMed, Embase and Cochrane Library databases. Finally, four RCTs with 551 patients were included in our study. We pooled 551 patients from 4 RCTs. Compared with placebo, an increased risk of adverse effects was observed in our analysis. After using esketamine, the risk of nausea (RR = 2.34, 95% CI, 1.04 to 5.25, P = 0.04), dissociation (RR = 4.54, 95% CI, 2.36 to 8.73, P < 0.00001), dizziness (RR = 3.00, 95% CI, 1.80 to 5.00, P < 0.0001), vertigo (RR = 7.47, 95% CI, 2.55 to 21.86, P = 0.0002), hypoesthesia (RR = 5.68, 95% CI, 2.06 to 15.63, P = 0.0008), sedation (RR = 3.96, 95% CI, 1.29 to 12.15, P = 0.02) and paresthesia(RR = 3.05, 95% CI, 1.07 to 8.65, P = 0.04)were significantly increased compared with placebo. Our synthesized data analysis revealed drug specific risk profiles. The most frequent adverse effects under treatment with esketamine were nausea, dissociation, dizziness, vertigo, hypoesthesia,sedation and paresthesia.

Yang, S., Wang, J., Li, X., Wang, T., Xu, Z., Xu, X., Zhou, X., & Chen, G. (2021). Adverse Effects of Esketamine for the Treatment of Major Depression Disorder: Findings from Randomized Controlled Trials. The Psychiatric quarterly, 10.1007/s11126-020-09871-x. Advance online publication. https://doi.org/10.1007/s11126-020-09871-x

Link to full text